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Biomedical subjects

M Rizzetto

Publications and source records attributed to M Rizzetto.

At least 235 records · Page 13Linked to original sources
PubMed1990

Riboprobe assay for HDV RNA: a sensitive method for the detection of the HDV genome in clinical serum samples.

We have used a new hybridization assay for the detection of the genome of hepatitis delta virus (HDV) in serum using a strand-specific RNA probe obtained by transcription of a recombinant riboprobe. This assay was tested on a panel of 30 sera from HBsAg carriers with hepatitis delta antigen (HDAg) in the liver. The riboprobe assay detected HDV RNA in the serum of 83% of the patients, while 63% were positive using the DNA hybridization assay. HDAg was detected in 73% of the same sera by immunoblotting. The riboprobe assay was also compared to other assays on serial samples from an experimentally infected chimpanzee. These results demonstrate that the Northern blot assay using the RNA probe is more sensitive than the homologous DNA probe for the detection of HDV in serum and is also more sensitive than the immunoblot assay for HDAg. The riboprobe assay is the most sensitive of currently available methods to measure HD viremia.

Adult↗
PubMed1990

Diagnostic significance of IgM antibody to hepatitis delta virus in fulminant hepatitis B.

The prevalence of hepatitis delta virus (HDV) infection was studied in 25 adult patients with fulminant hepatitis who were admitted consecutively to our unit from February, 1986, to September, 1988. Enzyme and radioimmunoassays were used for the detection of serological markers of HAV, HBV, and HDV (HDAg, IgM anti-HD, total [IgG] anti-HD) infections. Two hundred twenty-nine serum samples (three to 19 samples/patient) were tested for serological markers of HDV infection. Of the 25 patients, 17 (68%) were HBsAg-positive, and the remaining eight (32%) were HBsAg-negative on admission to the hospital. All patients were seropositive for IgM anti-HBc. Serological markers of HDV infection were detected in 13 (52%) of the 25 patients. In particular, HDV infection was observed in nine (53%) of the 17 HBsAg-positive and in four (50%) of the eight HBsAg-negative patients with type B fulminant hepatitis. Survival was 16.7% for patients with hepatitis B and 57.8% for patients with B and D coinfection. Coinfections were responsible for fulminant hepatitis in 100% of drug addicts and 40% in patients who were not drug addicts. All patients with HBV/HDV coinfections became seropositive for IgM anti-HD. The results show that HDV infection has a significant role (52%) in type B fulminant hepatitis in an area with a moderate prevalence of HBV infections, that it should be tested in cases with early clearance of HBsAg, and that it does not seem to be accompanied by a high fatality rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Monomeric (7S) immunoglobulin M antibodies to hepatitis delta virus in hepatitis type D.

The pattern of the immunoglobulin M antibody to the hepatitis delta virus distinguishes acute from chronic hepatitis D. Expression of the immunoglobulin M antibody to the hepatitis delta virus is relatively weak and short-lived in self-limited hepatitis but strong and persistent in chronic forms. To study the nature of the immunoglobulin M antibody to the hepatitis delta virus in acute hepatitis D and in chronic hepatitis D, antibody-positive sera were submitted to rate zonal centrifugation to separate monomeric 7S from pentameric 19S immunoglobulin M antibodies. Sera were from 6 patients with acute self-limited hepatitis, 4 patients with chronic hepatitis D, and 6 patients with hepatitis D progressing to chronicity. The immunoglobulin M reactivity was measured by a specific immunoassay based on capture of mu-chains by anti-mu linked on a solid phase. Only 19S antibody was found in acute hepatitis D. In contrast, all patients with chronic hepatitis D circulated 7S antibody in addition to the 19S antibody. In patients with progressive hepatitis D, both the 7S and 19S antibody variants were present at the onset of the disease. The difference in the antibody response between acute hepatitis D and chronic hepatitis D is not only temporal and quantitative but also qualitative. The expression of 7S antibody seems to be an immunologic event specific for chronic hepatitis D.

Acute Disease↗
PubMed1990

A new hepatitis B virus strain in patients with severe anti-HBe positive chronic hepatitis B.

In hepatitis B virus carriers who are anti-HBe positive despite ongoing viral replication (HBcAg in liver and HBV-DNA in serum) the natural course of hepatitis is severe and the response to interferon is low. We investigated whether a new hepatitis B virus (HBV) strain could be involved. A translational termination codon at the carboxyterminal end of the pre-C region responsible for the lack of HBeAg secretion was found in 18 of 19 HBV clones isolated from seven pedigreed patients with this clinical syndrome. The same findings were confirmed by direct sequencing. One of these patients underwent a liver transplant and HBV infection of the new liver resulted in high titered viremia and intrahepatic expression of HBcAg, without detectable HBeAg in serum. Another patient was superinfected by hepatitis delta virus (HDV) and developed high titres of total and IgM anti-HD. In spite of this, chronic hepatitis remained unchanged during 7 years of follow-up. These data strongly suggest that a viable precore minus mutant of hepatitis B virus is responsible for the lack of HBeAg in the serum of these patients. The HBV variant may explain the peculiar geographic distribution of anti-HBe positive hepatitis. The variations in the virus genome sequence may cause the more severe form of liver disease and modify the pathogenicity in the case of HDV superinfection.

Adult↗
PubMed1990

Hepatitis delta: the virus and the disease.

In general, the biological and structural properties of the hepatitis delta virus resemble those of the viroids and related satellite RNA viruses of plants. This resemblance has been strengthened by the discovery that, in analogy to the self-cleaving of some plant RNA viruses, hepatitis delta virus RNA possesses autocleaving and autoligating sites located in sequences that are homologous with highly conserved domains in the viroids. The catalytic properties identify the hepatitis delta virus as the first mammalian ribozyme. The current interpretation of the pathobiology of delta hepatitis rests on the postulates that the hepatitis delta virus invariably requires hepatitis B virus for infection and is highly pathogenic. Accordingly, delta hepatitis is thought to occur when hepatitis delta virus coinfects with hepatitis B virus or when it superinfects hepatitis B virus carriers. However, new evidence from the liver transplantation model suggests that hepatitis delta virus is capable of establishing latent, asymptomatic infections without the apparent assistance of hepatitis B virus: in this model, disease was only reactivated when hepatitis B virus also returned to the graft. Thus, hepatitis B virus superinfection on a latent hepatitis delta virus state may be a third pathobiological mechanism conducive to delta hepatitis.

Carrier State↗
PubMed1990

Hepatitis delta virus as a global health problem.

As a defective virus requiring helper functions of the hepatitis B virus (HBV), the hepatitis delta virus (HDV) develops only in patients with hepatitis B surface antigen (HBsAg); its presence aggravates the course of the underlying HBV infection. There is no specific prophylaxis against HDV, and its inactivation kinetics by physical and chemical agents are largely unknown. Thus, prevention of HDV in the HBsAg carrier at risk of superinfection is limited to environmental and barrier measures only. As normal persons are efficiently protected from HDV by hepatitis B vaccination, the risk of HDV is another indication for hepatitis B vaccination of at-risk individuals.

Hepatitis B↗
PubMed1990

Immunohistochemical research of HDV infection in Chinese patients with chronic liver disease.

The prevalence of HDAg in the liver of Chinese patients with chronic hepatitis and hepatocellular carcinoma was determined using direct immunofluorescence and immunoperoxidase. Overall, 6 patients (6.31%) out of 95 HBsAg carriers with inflammatory liver disease and neoplasia were found to be HDAg positive. HDAg was detected in the livers of 6 (7.59%) out of 79 chronic hepatitis patients. The relative frequency of HDAg in cirrhosis-B, CAH-B and CPH-B was 14.3%, 7.1%, and 5.89%, respectively. These results suggest that a sizeable number of HBsAg carriers are also carriers of HDV. In view of the large number of HBV carriers in China, the relatively minor but distinct presence of HDV represents an important health problem.

Carcinoma, Hepatocellular↗
PubMed1989

Immunohistochemical research on HDV infection in Chinese patients with chronic liver disease.

The prevalence of HDAg in the liver of Chinese patients with chronic hepatitis and hepatocellular carcinoma was determined by using direct immunofluorescence and immunoperoxidase. Six patients (6.3%) out of 95 HBsAg carriers with inflammatory liver disease and neoplasia were found to be HDAg positive. HDAg was shown in the liver of 6 patients (7.6%) among 79 patients with chronic hepatitis. The relative frequency of HDAg in cirrhosis-B, chronic active hepatitis B and chronic persistent hepatitis B was 14.3%, 7.1% and 5.9% respectively. These results suggest that a sizeable number of HBsAg carriers are superinfected with HDV. In view of the large amount of HBV carriers in China, the relative minor but distinct presence of HDV poses an important community health problem.

Carcinoma, Hepatocellular↗
PubMed1988

Delta hepatitis virus infection in Ethiopia.

The results of Hepatitis Delta virus (HDV) antibody determinations carried on 566 HBsAg positive serum samples from a population of 5270 Ethiopian military recruits are reported. The prevalence of anti-HDV among apparently healthy HBsAg carriers was 5.8%. The prevalence increases with age within the available range (18-30 years). Differences might exist by area of origin and ethnic groups. The distributions of HBV markers was similar in anti HDV positive and anti HDV negative individuals, possibly due to the relatively young age of the population and/or the hyperendemic condition of the area.

Adolescent↗
PubMed1988

Chronic HDV (hepatitis delta virus) hepatitis. Intrahepatic expression of delta antigen, histologic activity and outcome of liver disease.

The expression of intrahepatic delta antigen (HDAg) was studied in relation to the morphologic features of HDV hepatitis and the outcome of liver disease. The study was performed in 101 patients followed up for an average of 12 years; one or more liver biopsies were available from each patient, giving a total of 167 specimens. The histologic features were assessed using numerical scores. A significant positive relation was observed between the number of HDAg-positive cells and the extent of portal inflammation (Spearman's rank coefficient 0.75). The highest degree of inflammation and intrahepatic expression of HDAg was found before the elimination of the virus, while the outcome of HDV disease was unrelated to the severity of the initial morphologic lesion. These results suggest that the individual immune response may play an important role in the pathogenesis of HDV hepatitis.

Adolescent↗